1. The Field of the Invention
The present invention relates to down-the-hole tools and to hydro-percussive mechanisms for down-the-hole applications.
2. The Relevant Technology
Core drilling allows samples of subterranean materials from various depths to be obtained for many purposes. For example, drilling a core sample and testing the retrieved core helps determine what materials are present or are likely to be present in a given formation. For instance, a retrieved core sample can indicate the presence of petroleum, precious metals, and other desirable materials. In some cases, core samples can be used to determine the geological timeline of materials and events. Accordingly, core samples can be used to determine the desirability of further exploration in a given area.
Although there are several ways to collect core samples, core barrel systems are often used for core sample retrieval. Core barrel systems include an outer tube with a coring drill bit secured to one end. The opposite end of the outer tube is often attached to a drill string that extends to a drill head that is often located above the surface of the earth. The core barrel systems also often include an inner tube located within the outer tube. As the drill bit cuts formations in the earth, the inner tube can be filled with a core sample. Once a desired amount of a core sample has been cut, the inner tube and core sample can be brought up through the drill string and retrieved at the surface.
When cutting through ultra-hard formations, a constant force axial force, or thrust force, is applied to the bit as the bit is rotated resulting in shearing forces between the bit and the rock formation. The shearing forces break bits of material from the ultra-hard formation as the bit is rotated. While such a process can cut a core sample from ultra-hard formations, such a process may be relatively slow.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced